Trip Truck

big world - short life

Introduction To The Initial Fit Out Pages

The following Initial Fit Out pages are mainly concerned with the choice and fitting of ‘life support’ equipment. Our experience of motorhoming and boating, plus our intended use of the truck, broadly informed our choices in this regard. Of course, there is no right and wrong when it comes to the finer points of equipment choice and much depends on the kind of travel intended. As our own preference is to be out in the middle of nowhere, it is important for us to be able to self-sustain as much as possible. To meet this need, relatively large capacities of fuel(s) and water are helpful; as is engineering simplicity, component reliability, and the availability of auxilliary systems. If one life support system should fail, that system should ideally have been chosen and built in such a way that will allow an attempt at repair in the field, and if that is not possible, then there should ideally be a standby system in place. No heating whilst pursuing the Northern Lights in November would not be condusive to comfort...

The water tank has a 345 litre capacity. On ordering it from CAK - as is required by the company - I specified the various fittings to suit our build. These included a 'three-quarters empty' float switch as well as twin inspection / cleaning hatches, plus the usual array of filling / take-off fittings. Keeping with the simplicity theme, I didn’t want the bother of fitting any of the various probes / multi level sensors normally found in motorhome water tanks as these are very often unreliable and nearly always inaccurate. Our system does just what it says on the tin and a warning light illuminates (extinguishable by a manual switch) when we are down to our last 80 litres or so. This gives us, with our usual rate of use, about four or five days to find more water.

I arranged the fill and breather points to be isolated via taps from inside the truck as I didn’t want to go through the outer wall with a conventional filler / breather arrangement. For me, an outside filler is just one more thing for unwanted hands to tamper with – and one more set of keys to lose. The tank is filled by connecting a hose to a simple connection point within the truck (accessible from standing in the sheltered position just outside the main entrance door) with the additional option to pour / siphon from portable containers straight into the top of the tank via the inspection hatches in the event of no pressurised supply being available. The tank can also be tapped-off and drained via a fixed tube situated beneath the floor to externally supply fresh water for bike bottles / cleaning windows / washing down muddy boots etc.

I constructed a very substantial aluminium cradle to hold the tank in situ and, to prevent any chafing, ran strips of closed cell foam in critical areas. Furniture is also constructed tight up to the tank to prevent any movement whatsoever. The tank feeds a Shurflo 24V 30psi water pump which takes care of distribution. The pump itself is manually switched to allow it to be isolated when driving / left unattended. If the plumbing failed at any point, it goes without saying that 345 litres of water pumped around the interior would make something of a mess. All the electrical switches for the water system, as throughout the truck, are from CBE who make a very useful array of switchgear and monitoring equipment for the self-builder.

Fresh Water

Electrical Supply System

The electrical system is essentially a 24V system comprising 2 x 12V batteries wired in series. These feed, via a fuse block and remote switches, the main appliances on the truck including the water pump, diesel heater, and the compressor fridge. The 24V system also feeds a 1800W inverter sourced from Road Pro which powers a 'mini' 230V ac circuit. This mini ac circuit has only two purposes: to run a 750W heating element in the calorifier when we need to raise the temperature of our stored hot water by a few degrees, and to power a 1200W hairdryer from time to time. The inverter is generally only run when the truck engine is running.

Additionally, I also installed a single 12V stand-alone battery, the purpose of which is to provide power to supplementary equipment including our LCD TV / DVD, music player, LED lighting, and mobile phone charging points. Keeping with the 'redundancy' theme, this battery could also be put to use as a spare should one of the 12V batteries in the 24V bank fail. The 12V stand-alone battery is charged automatically from the 24V 'bank' via a 24V - 12V Toolbox Shop sourced Durite battery-to-battery charger.

If one battery, or the B2B charger, were to fail, then the 12V circuits on the truck can still be used, but are instead powered from the 24V battery bank via a 24V DC - 12V DC converter. Switching from the stand alone 12V supply to the 24V-12V converted supply is a matter of flicking one switch which operates two relays. One of these is a simple on/off relay which powers the converter up, and the second (a change over relay) simultaneously switches the input from the stand-alone battery to the DC-DC converter supply. For those that are interested, the 12V stand alone battery supply feeds T87a, the 24V-12V converted supply feeds T87: both output via T30 to the 12V fuse block.

The entire system is charged solely from the truck's twin 24V alternators. As our truck was the NATO 'Fitted for Radio' variant, then it came with this useful high capacity charging system as standard. One alternator just charges the engine batteries and the second alternator charges both the engine and leisure batteries from separate terminals. I hope it never happens, but this twin arrangement could be jury-rigged in the field to have one alternator provide all the power needed in the event that the other failed.

As mentioned elsewhere, we have only incredibly rarely bothered with an external hook-up so again, keeping it simple, we decided to do away altogether with any external AC system. Also, as our style of travel means we move on just about every day, we have yet to see the need for solar / wind power generators, though we did use both to good effect on our narrowboat where we'd often moor for a week or so in the same place.

Most of the wiring hardware was obtained from Vehicle Wiring Products who have been a reliable supplier over many years of tinkering.